Agronomy Notes

September, 2002

Contents:

SOIL TESTING
FORAGES AND PASTURE
CORN
SORGHUM
WHEAT
RICE
SOIL and NUTRIENT MANAGEMENT
COTTON

 

 

SOIL TESTING

Dr. Keith Crouse

Early fall is a good time to improve pastures and hays fields. During the past few weeks we have been receiving soil samples that were cropped for cool season forages. Soil acidity appears to be the major fertility problem for these fields. This can easily be corrected by apply recommended lime. Most cool season grasses grow best at a pH level above 6.0.

Depending on the crops, approximately 30 lbs of potassium per ton hay removal and potassium removal from a soil could be even higher on the hybrid bermudagrass fields. Potassium roles in plants are to reduce lodging and increases winter hardiness and disease resistance; increases photosynthesis; carbohydrate metabolism and breakdowns and translocations starches; activates various enzymes; adjusts stomatal movement and water relations. Potassium fertilizer may need to be applied to our hay fields and fertilizer recommendations depend on the crop being grown. Therefore, to know what is needed, take a good random soil sample and have it tested.

Remember that you should always take the soil sample from a uniform area that is usually about 10 acres or less in size. Take enough separate cores within the soil area for a representative soil sample. Generally, this is about 15 to 20 cores. Take your soil cores from the surface to plow layer. Mix your soil cores thoroughly. Send a full soil box or a pint of soil, completed form(s) and payment of $6.00 per sample.

FORAGES AND PASTURES

Dr. David Lang

Store Your Hay- Whether you store hay in the barn or outdoors, you need to store it properly. First, know where and when the forage was cut for hay. Also, keep track of the type or mixture of forage species and the stage of maturity at the time of cutting. Next, take a forage sample and send it to the State Chemical Lab (PO Box CR, Mississippi State, MS 39762) along with the forage sample form you obtain from your County Extension Office. Ask your County Extension Office if you can borrow their hay sampler. Take the core sample from the round sides of several representative (same cutting) round bales (not the flat ends) or from the long end of a square bale. Each Mississippian is allocated up to

$100 of testing from the State Chemical Lab (not just hay, but other analyses as well). They send the results to Mr. Blair McKinley, Beef Specialist in Animal and Dairy Sciences at MSU, who interprets the results and makes ration suggestions based on the lab figures and other information you provide on the forage sample form. Good high quality forage reduces the need for purchased feeds and supplements, but you must know the nutritive value. Livestock producers in South Mississippi may also be able to have their forage samples tested for free at the Franklinton, LA Dairy Research Center - see your County Extension Office for details.

Hay must be protected from rainfall and ground moisture or a significant portion will be lost to spoilage and decomposition. Bales stored outside on the ground lose as much as 300 to 400 lbs. of actual weight over a year's time. Do all that you can to break contact of the bale with the soil. Ground moisture is wicked up into the bale causing considerable deterioration. Be sure to store your bales on a well-drained hilltop where they can be exposed to a good amount of sunshine and leave some space between each bale to allow for good ventilation. Feed your hay according to the nutritional needs of your animals based on the forage quality of each hay lot.

The hay quality you store is only as good as the forage quality on the day you bale. Among the several factors which effect hay quality, plant age or maturity is the single most important factor. As the plant grows from vegetative to flowering there is a marked decline in forage quality. The best combination of good yield and high forage quality is when the forage just starts to flower. If you wait several days after flowering you may get more yield, but the nutritional value will change from being suitable for young, growing animals to only being suitable for maintaining mature animals. You need hay for all classes of livestock you keep.

Some other critical factors which affect hay quality include type of forage and season of growth. Cool season grasses (Tall Fescue, Ryegrass, Oats, Wheat, etc.) generally have much better quality than warm season grasses (Bermudagrass, Bahiagrass, Dallisgrass, Pearl Millet, etc.). Legumes (Clovers, Lespedeza, Alfalfa, etc.) add quality to any hay or pasture mixture. Summer grasses have the lowest quality, but if you harvest at a 30-35 day interval, quality will be improved. Rain during hay making can leach out nutrients and cause molding, but a rain event within a day of cutting is far less damaging than rain after 2-3 days of drying. Watch the weather forecasts, but remember, the older your stand of hay gets the more it declines in nutritional quality.

CORN

Dr. Erick Larson

Borers Necessitate Early Harvest - Last month I urged producers to try to complete their harvest before Labor day in northeast MS and the Delta, because of southwestern corn borer infestation in these regions. I strongly encourage producers to scout their corn fields and compare the lodging potential versus the moisture dockage incurred with early harvest. Numerous observant growers began noticing substantial (approximately 50% in some cases) stalk lodging resulting from southwestern corn borer girdling activity around the third week of August. Third-generation southwestern corn borers literally cut stalks down by girdling the stalk internally a few inches above ground level. Splitting the remaining attached stalk will reveal the overwintering larvae below ground level. Fall discing will likely reduce southwestern corn borer survivability by destroying this overwintering site.

SORGHUM

Dr. Erick Larson

Head Sprouting: The extraordinary rainy, humid weather last year prior to labor day promoted extensive kernel sprouting in many row crops, especially grain sorghum. Extensive kernel sprouting devastated unharvested sorghum in the south and central Delta last year. The only way to prevent sorghum kernel sprouting is to harvest it before environmental conditions encourage moisture accumulation. Sorghum is more susceptible than corn to pre-harvest sprouting (kernel moisture of 23-25% and 80-90 degree F conditions are ideal). Fortunately, September is normally one of the driest months of the year. However, sorghum growers may consider mechanically drying sorghum or taking some moisture dockage to avoid environmental exposure capable of promoting kernel sprouting.

Dessicant/Sorghum Moisture: After sorghum kernels reach physiological maturity, application of a pre-harvest dessicant will not influence kernel moisture. Sorghum physiological maturity is signified by a hard kernel and presence of a black spot opposite the embryo at the base of the kernel (similar to the black layer in corn). Kernel moisture will likely be 25-30% at physiological maturity. Kernel drying rate after physiological maturity is entirely dependent upon environmental conditions. Application of a pre-harvest dessicant may aid harvest progress by killing green vegetation and immature kernels on "sucker" heads on late tillers. The presence of these sources in a combine-harvested grain sorghum sample would raise measured moisture content of the sample.

WHEAT

Dr. Erick Larson

Wheat Varieties - The 2002 MSU Wheat Variety Trials are now available on the MSUcares.com website or at your county extension office. Variety evaluation should be based primarily upon yield history (particularly on different soil types or management regimes), plant characteristics (including maturity, straw strength and height) and disease resistance for predominant pathogens in the region. Wheat variety suggestions ("the short list") and variety characteristics are listed on the MSUcares.com wheat web site: www.msucares.com/crops/grain/index.html.

RICE

Dr. Joe Street

Initial indications are that yields are better than last year and if the late rice is as good as the early rice, this is going to be another record year for rice yields. The August rains caused some lodging but otherwise the crop looks good. So far, quality is excellent with very little stinkbug damage. Most of the rice is milling above the 55 percent whole grain standard and should bring a milling yield premium.

In the late maturing rice, continue to scout for stinkbugs. The stinkbug population has been increasing during the past weeks especially around corn and milo. The threshold for stinkbugs during the first two weeks after heading is 3 per 10 sweeps. During the later stages, the threshold is 5 per 10 sweeps.

In general, diseases have not been a severe problem. Weather conditions were conducive to sheath blight but it did not move up the plants in most locations. Blast developed in Louisiana and Arkansas but I have seen only one case in Mississippi. Kernel smut is not widespread on the early rice but false smut is becoming more prevalent especially on the later planted rice. Much of the rice was treated for kernel smut and while fungicides will not control false smut, they will reduce its severity.

Although initial quality is good, post-harvest management is essential for maximum milling yield. Do not leave high moisture (18-20%) rice in the combine or truck over 24 hours or leave lower moisture (16-18%) rice for more than 48 hours. Rice needs aeration to avoid heat damage, which develops into stained grains.

Avoid drying high moisture rice with heated air above 90 degrees and high volumes of air. Rapid removal or moisture can reduce milling yield. Set heat to 85-90 degrees for rice above 15 percent moisture. When the rice moisture reaches 15 percent, 95-degree heat may be used. Avoid placing rice with a moisture difference of greater than 3 percent in a bin for drying. Try to avoid placing high moisture on top of lower moisture rice.

After drying to 12-12.5% (13% on top) and the moisture has stabilized for 7 to 10 days, rice should be cooled to 45 to 50 degrees at 40-60% humidity as soon as possible. Keep the top of the grain level in the bin because moisture will migrate to the top center of the bin. Once rice is cooled, check the temperature in the center of the bin and under vents every two weeks. A cotton module thermometer is good for checking temperature. After November, do not add high heat because bins will sweat if heated during the day and cause moisture to accumulate. Monitor the center rice layer closely. If there is any indication that moisture of temperature is increasing, either aerate the rice or mix it by moving rice from one bin to another. With the abundance of rice on the market, quality must be maintained.

September is Rice Month so eat a little extra rice during September and support the rice industry. The Annual Rice Luncheon sponsored by Delta Rice Promotions and the Bolivar County Farm Bureau will be September 20, at Delta State University from 11:00 a.m. to 1:00 p.m. Plan to attend and enjoy excellent rice dishes from across the Delta.

SOIL and NUTRIENT MANAGEMENT

Dr. Larry Oldham

DATE TO REMEMBER: Agronomic Professional Continuing Education Workshop, February 11-14, 2003 at the Bost Extension Center, MSU Campus, Starkville.Nutrient management is a systematic method of developing a plant nutrient budget for crops. It begins with simply knowing your soils and fields, and being realistic about their production capability. Two things bring this about: a soil survey and current soil tests.Being realistic allows you to determine what your crop nutrient use will be, and allow you to develop a plan to sustain your crops economically. In addition, using a planning process facilitates assessment of whether environmental risk from nutrient movement is possible.Nutrient managers should also keep records of nutrient applications, including date, material, rate, and method of application.Also record the Best Management Practices you used in the process. These are proven, economical, and simple ways to improve your profitability and protect the environment.Some BMP's include:using soil testing and following the recommendations,using commonsense, attainable yield goals in nutrient planning,updating and calibrating application equipment,keeping fertilizer materials away from surface waters,using cover crops to minimize soil movement,using application buffer zones, andkeeping water on the soil as long as possible before runoff.

COTTON

Dr. Will McCarty

Even though this crop had a cool start, it looks like it will do a little better than OK. There are some areas where dry weather will hurt yields but I feel that we have an excellent chance of making and/or exceeding the USDA production estimate. The August Crop Production Estimate placed this crop at 759 pounds of lint per acre from some 1,170,000 harvested acres. As I said, with good harvesting weather we have a good chance of exceeding this estimate - however, do not count the crop till it is bagged and tied.

Boll Counts for Yield Estimation - Generally speaking, counting bolls per acre can provide you with a pretty good estimate of the number of bolls per acre in a field, not much else. Using boll counts to estimate yield can be variable depending on boll size variability, harvest efficiency and gin turn-out. As a rough rule, it takes about 127,000 - 128,000 4.5 gram (seed cotton) bolls to produce a bale of cotton. That is at 38% turn out and no consideration for harvest efficiency. More realistically you are looking at about 150,000 bolls being required to produce a bale of lint. This may vary from variety to variety, from field to field, and from year to year. Therefore, boll counts are perhaps better than nothing at estimating yield, but not much. For those that like to count bolls and estimate yields, Table 1 contains some information that may help. Table 1 presumes a 35% turnout value and calculates estimated yields for several boll weights and row spacings. To use this table do the following:

1) determine row spacing in inches

2) determine the number of harvestable bolls per row foot. To do this , count the bolls five or ten foot of in three to five locations in the field and calculate an average per foot.

3) determine boll size. To do this pick samples of at least fifty bolls per location from several locations in the field. Weight them on an accurate scale and calculate an average boll weight. When picking bolls it is important to pick bolls from all possible size classes on the plant.

Alternative method to determine boll size. Select representative individual plants from several locations in the field. Count all harvestable bolls per plant, weight them and calculate an average. Doing this will insure that you include bolls from all size classes. See Table 1 at the end of this article.

Below are a few tips to consider as we finish this crop and prepare for next year:

Variety Selection - Post defoliation is an excellent time to make critical observations of all varieties in your area. Look very closely at your varieties and varieties planted in your area on similar soil types to your own. Look at plant height, node of first fruiting branch, fruit retention, boll size, boll integrity, presence of diseases such as vert wilt etc., root growth and crop uniformity. Make notes about each variety - so you will not forget what you see - and then record yields of each variety after harvest.

Tillage decisions - Interest in no-till, reduced till production has increased greatly. The main driving factor in this decision and movement is economics - (labor, machinery, time = money). Technology exist today to allow growers to produce cotton in reduced till systems. There are so many options to consider there is no way to address them here. If you are interested in no-till or reduced-till cotton production, give your local county agent a call and he will be glad to work with you in devising a system. Each time you can reduce a trip across a field it will allow you to either save money or work more cotton acreage for the same money. There are advantages and I feel that cotton production, on many soil types and soil resource areas, must move in that direction to remain sustainable.

Soil testing - Fall is an excellent time to take soil samples. I suggest you do so as soon as possible.

 

 

Department of Plant and Soil Sciences
Box 9555
Mississippi State, MS 39762

Will McCarty, Ph.D.
Extension Leader

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